CA2074120C - Pipeline inspection vehicle - Google Patents
Pipeline inspection vehicleInfo
- Publication number
- CA2074120C CA2074120C CA002074120A CA2074120A CA2074120C CA 2074120 C CA2074120 C CA 2074120C CA 002074120 A CA002074120 A CA 002074120A CA 2074120 A CA2074120 A CA 2074120A CA 2074120 C CA2074120 C CA 2074120C
- Authority
- CA
- Canada
- Prior art keywords
- vehicle
- spring
- sledge
- pipeline
- housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
- F16L55/28—Constructional aspects
- F16L55/40—Constructional aspects of the body
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
- F16L55/28—Constructional aspects
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/005—Investigating fluid-tightness of structures using pigs or moles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L2101/00—Uses or applications of pigs or moles
- F16L2101/30—Inspecting, measuring or testing
Abstract
A pipeline inspection vehicle comprises a body 18, an eletromagnet 20 for generating magnetic flux, and two foil packs 24, 26 for conducting the flux into and out of the pipewall 10. An array of defect sensors is arranged around the body 18, each sensor being mounted on d respective assembly 28.
Each assembly 28 comprises a steel sledge 40 which runs along the pipewall and which is secured to a sensor housing 42. A length of belting 44 is sandwiched between the two and end portions form a leading member 46 and a trailing member 48 linking the sledge to the vehicle. Each assembly 28 is positioned against a spring 64 which is also positioned against the vehicle.
The assembly collapses out of the way when the vehicle traverses a sharp bend and the foil pack 24 is deflected to the right. The two members 46 and 48 both counteract the force of the spring 64 when the sledge crosses a void in the pipewall. However, only the leading member 46 is effective during normal running of the sledge along the pipewall to transfer the motion of the vehicle to the sledge.
Each assembly 28 comprises a steel sledge 40 which runs along the pipewall and which is secured to a sensor housing 42. A length of belting 44 is sandwiched between the two and end portions form a leading member 46 and a trailing member 48 linking the sledge to the vehicle. Each assembly 28 is positioned against a spring 64 which is also positioned against the vehicle.
The assembly collapses out of the way when the vehicle traverses a sharp bend and the foil pack 24 is deflected to the right. The two members 46 and 48 both counteract the force of the spring 64 when the sledge crosses a void in the pipewall. However, only the leading member 46 is effective during normal running of the sledge along the pipewall to transfer the motion of the vehicle to the sledge.
Description
` ~ l - 2~7~120 PIPELINE lh.~r~;L1~1~ VEHICLE
The invention relstes to pipeline inspection vehicles.
mLhe invention is described in terms of a vehicle which inspect3 ductile iron gas diDtribution pipelines, the vehicle being towed through the pipeline by means of a flexible member, such QS a cable, attached to a winch. However, the invention is applicable quite generally and includes vehicle8 for u9e in inspecting gas or oil tr~n~ -; cc~ n pipelines, or pipelines for conveying water or other liquids which in most cases are propelled through the pipeline by a pressure difference across the vehicle owing to the pressure difference applied to drive the fluid through the pipeline.
British patent spe~ifie~ti~n No. GB-B-1535252 describes a pipeline inspection vehicle for inspecting gas trJ~n~ sir~n lines. The vehicle has an array of sensor mountings arranged around the body of the vehicle. Each sensor is mounted on a metal plate or sledge adapted to run along the inside surface of the pipeline to be inspected. The leading end of the plate is connected by a flexible member to an anchorage on the vehicle. A metal spring also mounted on an anchorage on the vehicle has two spring arms, the first of which bears against the flexible member and the second of which bears against the trailing end of the plate.
Thus, the plate is urged towards the pipeline by spring forces applied at its ends.
~' ~ - 2 - 2074 1 20 The object of the invention i8 to provide an in~rect~n vehicle in which the spring o~ each de~ect sensor exerts on the respective sledge substantially only a ~orce normal to the pipe w811.
According to the present invention there is provided a piE~eline inspection vehlcle for detecting defects in the wall of the pipeline comprising a body, two ~paced apart flux conductors for engaging the inside of the pipeline, and means for generating flux either electromagnetically or by p~rr~n~nt n~n~t;P~, said flux being capable of circulating in a path including said wall, one of said ~.
conductors, ~aid body or return path members secured to said body and the other of said conductors, the inspection vehicle further comprising an array of defect sensor3 arranged between said conductors, each sen30r being mounted on an assembly which comprises a housing ~or the sensor, a sledge secured to the housing, and a spring interposed between said sensor housing and the body, in such a way that, when the vehicle is placed in the pipeline, the spring biases the housing and the sledge away from the body toward the inside wall of the pipeline, said array being a circular array arranged around said body, each defect sensor being provided with its own assembly, in each assembly there being a leading member and a trailing me~ber ~ nrl;ng from the sledge to respective anchorages which are spaced apart in the direction of the length of the vehicle _~
along a surface which i~ provided on, or connected to, said body and which is radially opposed to the housing, the anchorages being separated by a greater distance than the length of the sledge, said spring being positioned between ~aid leading and trailing members against the sen~or housing and against said surface, said leading and trailing members being inextensible and each being readily collapsible under forces tending to make its ends become closer.
B
- 2a -Prefer_bly each member comprises belting made of polymeric fibres.
Preferably, each said spring is made of IIVII - -A~ ` elastomeric material.
r ~c~i ls of the invention will now be described by way of example with reference to the A~- _ ylng drawings:
B
~ ` _ 3 _ 2074 1 20 Figure 1 is a longitudinal vertical ~LU~ Lion through the upper part of a first embodiment of pipeline ;nqpect;nn vehicle;
Figure 2 is a scrap vertical end-elevation through the spring of the defect sensor 8hûwn in Figure 1 ûn the line II-II in Figure l;
Figure 3 is a 6crap longitudinal vertical section through part of the defect sensor shown in Figure l;
Figure 4 is a front view of the front foil pack; and Figure 5 shows a secûnd ~ ` of vehicle.
The drawings shûw part of a pipeline ;ncpert~ n vehicle for ;n~roct;ng ductile cast iron gas distribution pipelines, in this case 12" pipelines (ie pipelines having nominally a 12", 3ûO m; 11; ~ inside diameter~ . The invention i8 Arpl;~Ahl~ to vehicles for ;ncpect;n~7 different sized pipelines, eg 6" and 8" gas distribution pipelines, and also steel gas tr~no~;CC;I~ lines having inside diameters of, say, 6" and above. The invention is also applicable to vehicles for inspecting non-gas pipelines, such as steel water or oil or other pipelines, for example.
In this example, the pipeline is in~pe~ to~l while it is "dead", ie, without any gas being present in it, and the vehicle is intended to be pulled through the pipeline by a cable attached to a winch. In trAn~ ion lines, the vehicle would normally be equipped with cups engaging the pipe wall and the vehicle p~-207412~
would be propelled by a difference in preasure ~developed across ths CUp5) in the product being conveyed by the pipeline.
Other drive options which are possible include the use of a tethered vehicle driven by drive cups engaging the pipe wall (eg the vehicle could be tethered by the umbilical cable). m~he pressure difference across the cups may be due to air blown along the pipe, in the ;ncpect;Gn of "dead"
pipelines, or where the pressure would be high enough the pressure difference across the cups could be due to gas moving in the pipeline as in medium pressure (and higher) distribution lines; also included i3 the use of a tractor vehicle to pull the inspection vehicle or to have inCpe~ti~n facilitiea included in the tractor vehicle. A tractor vehicle is usable in gas distribution lines, gas tr~n~miCC;~ lines, and water or oil or other lines .
In Figure 1, the mini bore of the pipeline 10 is shown at 12 and the maximum bore of the pipeline 10 is shown at 14. The pipeline 10 is made of ductile cast iron and the bore varies between the maximum and minimum v~lues shown.
The vehicle 16 consists of the following main c a body 18; an ele,LL~ ic coil 20 wound on a former 22 packs of foils 24, 26; and thirty-six assemblies 28 (only one of which is shown) equiangularly arranged ~round the body 18 of the vehicle 16.
Each pack of foils 24, 26 is made up of a number of foils each having the shape shown in Figure 4. This shape preferably comprises twelve fingers 25.
For different sizes of vehicle there m~y be different numbers of fingers.
For example, the six inch vehicle may have packs of foils in which each foil has nine fingers. The eight-inch vehicle has twelve fingers per foil, as in the present case. In the case of the six-inch vehicle eighteen sensors are preferred and in the case of the eight-inch vehicle, twenty-four sensors are preferred .
In modified vehicles the foils may be replaced by assemblies of bristles.
However, in this example the use of foils gives a ma~or advantage in that it allows a smaller occupied volume given the required metal area for adequate flur~ trAnr~m;Cc;l~n into the pipe wall. In this specification each of the packs 24, 26 or each of the A~ of bristles is referred to by the exoression "flux conductor". The function of the foil packs 24, 2~ ~
is explained below The vehicle in this case runs on the packs of foils without any other suspension com~ponent engaging the wall of the pipe. Alternative forms of vehicle may use wheels on the vehicle running along the pipewall in order to support all, or some of the wei~ht of the vehicle. The wheels may be displaceable relative to the body against springs. Instead of, or in ~ddition to, wheels the weight of the vehicle may be p~rtly or wholly supported on the drive cups referred to ~bove.
Each assembly 28 comprises an austenitic stainless steel sledge 40 which is secured to a sensor housing 42 with a length of belting 44 sandwiched between the two. The end portions of the belting 44 form a leading member 2D7~12~
46 and a trailing member 48 which link the leading and trailing ends, respectively, of the sledge 40 to the vehicle. The belting 44 is m~de of polyurethane coated polyester fibres and is fiubstantially ;n~Ytonc;hle.
The ends of the members 46, 4& are each held by a screw 50 (Pigure 3) which ha3 a rounded head 52 and retains a washer 54 having a rounded edge portion 56 against the belting 46 or 48. The screw 50 retains the member 46 or 48 against a stainless steel pressing 58 forming a base plate, itself retained in position on the outer edges 60, 62 of the former 22.
The assembly 28 is p~;t;~n~d against a spring 64, which is also positioned against the vehicle, or rather against the respective pressing or base plate 58. The spring 64 is approximately of 0 form and is made of polyurethane elastomeric material. The spring 64 ha3 a flattened shape at 66 where it engages the base plate 58. The spring 64 is retained in position against the base plate 58 by a pin 68 which engages holes in the sides o~ the plate 58, which is of U-section. The spring 64 is retained at its opposite end by ears 70 formed on the sensor housing 42, the ears 70 extending one on each side of the spring 64 to retain it ~gainst sideways displacement normal to the plane of the spring 64.
The ~ncp~ct;~n vehicle 16 is shown in the condition which applies to the vehicle before it is inserted in the pipeline. Assuming the vehicle is intended to move in the direction o~ the arrow 30 shown in ~igure 1, when the vehicle 16 is inserted in the pipeline the foil packs 24, 26 would be deflected to the right so as to curve as indicated by the ghost outlines at 32 and 34.
~ ` _ 7 _ 2074~20 The assemblies 28 would also be deformed and while the vehicle 16 is stationary in the pipeline, the members 46, 48 are slack and only the spring 64 is effective to exert a force on the sledge 40 which i8 subgtantially normal to the wall of the pipeline.
When the vehicle 16 moves (say in the direction of the arrow 30 shown in Figure 1~ the leading member 46 becomes taut and the motion of the vehicle is transmitted to sledge 40 by the member 16. The trailing member 48 becomes slack and does not play any part in the control of the as6embly 28 so long as the sledge 40 runs along the inside of the pipewall.
When the sledge 40 tr~vels across a void in the pipework tfor example where a br~nch pipe joins the pipeline) the sledge 40 moves radially outwardly and both leading and trailing members 46, 48 act to exert inwardly directed forces on the sledge 40 to counteract the outward force of the spring 64.
The vehicle 16 is designed to travel backwards, should it prove; hl~
to move it forward. In that caso, the roles of the members 46, 48 are reversed. The foil packs 24, 26 would be deformed in the opposite sense, curving towards the left iristead of towards the right.
Each assembly 28 must accommodate variations in the bore of the pipeline 10 and side-to-side motion of the vehicle within the pipeline. ~urthermore, the vehicle is required to negotiate bends in the pipeline. Such bends may be as tight AS one diameter, that is the radius of curvature of the bend ~measured to the pipe centre) is equal to the intern~l diameter of the bend.
Such a bend is especially severe in the case of 6" pipe. This is shown in - 8 - 2~74~ 20 Figure 5 in which a 6" vehicle is shown negoti~ting a one diametor bend in distribution pipeline. The assembly 28 at the inside of the bend is shown in the condition it has when the vehicle i8 out3ide the pipeline, however.
In negotiating such a bend the sensor assembly 28 at the inside of the bend is required to collapse completely. This is possible owing to the nature of the leading and trailing members 46, 48. Under such conditions, the foil pack 24 at the inslde of the bend would bo roquirod to be deflocted right over until tho roarmost foil lay against the stop 70 (shown in Figuro6 1 and S) carried by the vehicle body 18, and against the upper edge 72, of the wings of the pressing 58. The foil pack 26 would be heavily deformed, adjAcent to the outer wall of the pipeline, and the rearmost foil would conform to the stop 74 (shown in Figure 1 and 5) carried by the vehicle body 18 .
Under certain conditions, the spring 64 might ongage the leading member 46 and tho trailing member 48.
For example, the size of tho pipe might demand a spring of such rhAr ~rtPri ctic3 that the 8pring occupiog nearly the whole of the space between the leading member 46 and the trailing member 48. Under running conditions in the pipeline 10 the spring 64 might cause the leading member 46 to bow outwards.
~owever, even under such conditions the spring still exerts a force on the sledge 40 which is substantially normal to the pipewall. Also, the motion of the vehicle is still transmitted to tho sledge 40 by the leading member 46 notwithstanding its bowed shape.
t As shown, the vehicle 16 is intended normally to travel in the direction of the ~rrow 30 shown in Figure 1, bein8 pulled by a haulage cabl~ tnot 3hown) l~ttached to 2 3wivel assembly 60 mountod on a pin 62 ~ecured to the leading end of the body 18. Another heulage cable ~not shown) for retrieving the vehicle 16 in reverse is attached to the eye 64 secured to the trailing end of the body 18.
The incpect~nn is carried out using the flux leakage method. A powerful magnetic field is generated by the eleL:L~, v c coil 20 and transferred into, and out of, the wall of the pipeline 10 by the foil packs 24, 26.
Electric current to energise the ele, L-, ~ c coil 20 is supplied from the surface Vi2 an umbilical supply cable (not shown) connected to the coil.
Defects, such as loss of metal due to corrosion in the wall of the pipe, cause magnetic flux to leak out of the wall of the pipe, and this is detected by the sensor within the housing 42. Each sensor transmits a C~nt~n~
signal as the vehlcl~ movell through the pipel~ne And thl~ ~lgm~l, with t signals from the other sensors, is sent down a aecond umbilical cable (not shown~ which extends from the vehicle to a personal computer with a hard disc recording facility ~t the surface of the ground. The position of the vehicle along the pipeline is known from ~ monitor measuring the length of haulage cable paid out by the winch.
In some cases (for example where an, ' 1;CA1 supply cable cannot be used) the ele.L, v LTc coil 20 i8 replaced by a pr ~ magnet or magnets.
The magnetic flux creAted by the ele.L, v t 20 circulates in a path, which includes the wall of the pipeline 10, the flux conductor or foil pack . ~ . . i - lo - 2 0 7 ~ 1 2 ~
26, the return path provided by the body 18 and the othor foil pack 24 forming the other flux conductor.
In other modifications (not shown) the path m~y include flux rcturn paths which are formed by members carried by the body, instead of the body itself providing the return path. For example, where permanent magnets are used instead of an ele.~L ~ L, the LLLIU4, may be as shown in British patent specification No. GB-B-1535252. In that ~re~;fi~ t;r~l the magnets sre flat plates having the magnetic poles at their broad faces and those faces are arranged parallel to the pipe inside surface. The magnets are arranged one at each end o~ flux return path members arranged around the body. The members are mounted on springs so as to move radially inward and outward to allow changes in diameter of the pipeline to be accommodated.
The flux conductors are mounted upon the magnets. The assemblies 28 would in that aLLa1.6 be mounted not on the body itself but on a ring which is "floating". That is, the ring surrounds the flux return path members and i8 connected to them by radial posts which pass through holes in the ring. The ring can thus move radially with respect to the flux return path members as the vehicle negotiates bends.
The invention relstes to pipeline inspection vehicles.
mLhe invention is described in terms of a vehicle which inspect3 ductile iron gas diDtribution pipelines, the vehicle being towed through the pipeline by means of a flexible member, such QS a cable, attached to a winch. However, the invention is applicable quite generally and includes vehicle8 for u9e in inspecting gas or oil tr~n~ -; cc~ n pipelines, or pipelines for conveying water or other liquids which in most cases are propelled through the pipeline by a pressure difference across the vehicle owing to the pressure difference applied to drive the fluid through the pipeline.
British patent spe~ifie~ti~n No. GB-B-1535252 describes a pipeline inspection vehicle for inspecting gas trJ~n~ sir~n lines. The vehicle has an array of sensor mountings arranged around the body of the vehicle. Each sensor is mounted on a metal plate or sledge adapted to run along the inside surface of the pipeline to be inspected. The leading end of the plate is connected by a flexible member to an anchorage on the vehicle. A metal spring also mounted on an anchorage on the vehicle has two spring arms, the first of which bears against the flexible member and the second of which bears against the trailing end of the plate.
Thus, the plate is urged towards the pipeline by spring forces applied at its ends.
~' ~ - 2 - 2074 1 20 The object of the invention i8 to provide an in~rect~n vehicle in which the spring o~ each de~ect sensor exerts on the respective sledge substantially only a ~orce normal to the pipe w811.
According to the present invention there is provided a piE~eline inspection vehlcle for detecting defects in the wall of the pipeline comprising a body, two ~paced apart flux conductors for engaging the inside of the pipeline, and means for generating flux either electromagnetically or by p~rr~n~nt n~n~t;P~, said flux being capable of circulating in a path including said wall, one of said ~.
conductors, ~aid body or return path members secured to said body and the other of said conductors, the inspection vehicle further comprising an array of defect sensor3 arranged between said conductors, each sen30r being mounted on an assembly which comprises a housing ~or the sensor, a sledge secured to the housing, and a spring interposed between said sensor housing and the body, in such a way that, when the vehicle is placed in the pipeline, the spring biases the housing and the sledge away from the body toward the inside wall of the pipeline, said array being a circular array arranged around said body, each defect sensor being provided with its own assembly, in each assembly there being a leading member and a trailing me~ber ~ nrl;ng from the sledge to respective anchorages which are spaced apart in the direction of the length of the vehicle _~
along a surface which i~ provided on, or connected to, said body and which is radially opposed to the housing, the anchorages being separated by a greater distance than the length of the sledge, said spring being positioned between ~aid leading and trailing members against the sen~or housing and against said surface, said leading and trailing members being inextensible and each being readily collapsible under forces tending to make its ends become closer.
B
- 2a -Prefer_bly each member comprises belting made of polymeric fibres.
Preferably, each said spring is made of IIVII - -A~ ` elastomeric material.
r ~c~i ls of the invention will now be described by way of example with reference to the A~- _ ylng drawings:
B
~ ` _ 3 _ 2074 1 20 Figure 1 is a longitudinal vertical ~LU~ Lion through the upper part of a first embodiment of pipeline ;nqpect;nn vehicle;
Figure 2 is a scrap vertical end-elevation through the spring of the defect sensor 8hûwn in Figure 1 ûn the line II-II in Figure l;
Figure 3 is a 6crap longitudinal vertical section through part of the defect sensor shown in Figure l;
Figure 4 is a front view of the front foil pack; and Figure 5 shows a secûnd ~ ` of vehicle.
The drawings shûw part of a pipeline ;ncpert~ n vehicle for ;n~roct;ng ductile cast iron gas distribution pipelines, in this case 12" pipelines (ie pipelines having nominally a 12", 3ûO m; 11; ~ inside diameter~ . The invention i8 Arpl;~Ahl~ to vehicles for ;ncpect;n~7 different sized pipelines, eg 6" and 8" gas distribution pipelines, and also steel gas tr~no~;CC;I~ lines having inside diameters of, say, 6" and above. The invention is also applicable to vehicles for inspecting non-gas pipelines, such as steel water or oil or other pipelines, for example.
In this example, the pipeline is in~pe~ to~l while it is "dead", ie, without any gas being present in it, and the vehicle is intended to be pulled through the pipeline by a cable attached to a winch. In trAn~ ion lines, the vehicle would normally be equipped with cups engaging the pipe wall and the vehicle p~-207412~
would be propelled by a difference in preasure ~developed across ths CUp5) in the product being conveyed by the pipeline.
Other drive options which are possible include the use of a tethered vehicle driven by drive cups engaging the pipe wall (eg the vehicle could be tethered by the umbilical cable). m~he pressure difference across the cups may be due to air blown along the pipe, in the ;ncpect;Gn of "dead"
pipelines, or where the pressure would be high enough the pressure difference across the cups could be due to gas moving in the pipeline as in medium pressure (and higher) distribution lines; also included i3 the use of a tractor vehicle to pull the inspection vehicle or to have inCpe~ti~n facilitiea included in the tractor vehicle. A tractor vehicle is usable in gas distribution lines, gas tr~n~miCC;~ lines, and water or oil or other lines .
In Figure 1, the mini bore of the pipeline 10 is shown at 12 and the maximum bore of the pipeline 10 is shown at 14. The pipeline 10 is made of ductile cast iron and the bore varies between the maximum and minimum v~lues shown.
The vehicle 16 consists of the following main c a body 18; an ele,LL~ ic coil 20 wound on a former 22 packs of foils 24, 26; and thirty-six assemblies 28 (only one of which is shown) equiangularly arranged ~round the body 18 of the vehicle 16.
Each pack of foils 24, 26 is made up of a number of foils each having the shape shown in Figure 4. This shape preferably comprises twelve fingers 25.
For different sizes of vehicle there m~y be different numbers of fingers.
For example, the six inch vehicle may have packs of foils in which each foil has nine fingers. The eight-inch vehicle has twelve fingers per foil, as in the present case. In the case of the six-inch vehicle eighteen sensors are preferred and in the case of the eight-inch vehicle, twenty-four sensors are preferred .
In modified vehicles the foils may be replaced by assemblies of bristles.
However, in this example the use of foils gives a ma~or advantage in that it allows a smaller occupied volume given the required metal area for adequate flur~ trAnr~m;Cc;l~n into the pipe wall. In this specification each of the packs 24, 26 or each of the A~ of bristles is referred to by the exoression "flux conductor". The function of the foil packs 24, 2~ ~
is explained below The vehicle in this case runs on the packs of foils without any other suspension com~ponent engaging the wall of the pipe. Alternative forms of vehicle may use wheels on the vehicle running along the pipewall in order to support all, or some of the wei~ht of the vehicle. The wheels may be displaceable relative to the body against springs. Instead of, or in ~ddition to, wheels the weight of the vehicle may be p~rtly or wholly supported on the drive cups referred to ~bove.
Each assembly 28 comprises an austenitic stainless steel sledge 40 which is secured to a sensor housing 42 with a length of belting 44 sandwiched between the two. The end portions of the belting 44 form a leading member 2D7~12~
46 and a trailing member 48 which link the leading and trailing ends, respectively, of the sledge 40 to the vehicle. The belting 44 is m~de of polyurethane coated polyester fibres and is fiubstantially ;n~Ytonc;hle.
The ends of the members 46, 4& are each held by a screw 50 (Pigure 3) which ha3 a rounded head 52 and retains a washer 54 having a rounded edge portion 56 against the belting 46 or 48. The screw 50 retains the member 46 or 48 against a stainless steel pressing 58 forming a base plate, itself retained in position on the outer edges 60, 62 of the former 22.
The assembly 28 is p~;t;~n~d against a spring 64, which is also positioned against the vehicle, or rather against the respective pressing or base plate 58. The spring 64 is approximately of 0 form and is made of polyurethane elastomeric material. The spring 64 ha3 a flattened shape at 66 where it engages the base plate 58. The spring 64 is retained in position against the base plate 58 by a pin 68 which engages holes in the sides o~ the plate 58, which is of U-section. The spring 64 is retained at its opposite end by ears 70 formed on the sensor housing 42, the ears 70 extending one on each side of the spring 64 to retain it ~gainst sideways displacement normal to the plane of the spring 64.
The ~ncp~ct;~n vehicle 16 is shown in the condition which applies to the vehicle before it is inserted in the pipeline. Assuming the vehicle is intended to move in the direction o~ the arrow 30 shown in ~igure 1, when the vehicle 16 is inserted in the pipeline the foil packs 24, 26 would be deflected to the right so as to curve as indicated by the ghost outlines at 32 and 34.
~ ` _ 7 _ 2074~20 The assemblies 28 would also be deformed and while the vehicle 16 is stationary in the pipeline, the members 46, 48 are slack and only the spring 64 is effective to exert a force on the sledge 40 which i8 subgtantially normal to the wall of the pipeline.
When the vehicle 16 moves (say in the direction of the arrow 30 shown in Figure 1~ the leading member 46 becomes taut and the motion of the vehicle is transmitted to sledge 40 by the member 16. The trailing member 48 becomes slack and does not play any part in the control of the as6embly 28 so long as the sledge 40 runs along the inside of the pipewall.
When the sledge 40 tr~vels across a void in the pipework tfor example where a br~nch pipe joins the pipeline) the sledge 40 moves radially outwardly and both leading and trailing members 46, 48 act to exert inwardly directed forces on the sledge 40 to counteract the outward force of the spring 64.
The vehicle 16 is designed to travel backwards, should it prove; hl~
to move it forward. In that caso, the roles of the members 46, 48 are reversed. The foil packs 24, 26 would be deformed in the opposite sense, curving towards the left iristead of towards the right.
Each assembly 28 must accommodate variations in the bore of the pipeline 10 and side-to-side motion of the vehicle within the pipeline. ~urthermore, the vehicle is required to negotiate bends in the pipeline. Such bends may be as tight AS one diameter, that is the radius of curvature of the bend ~measured to the pipe centre) is equal to the intern~l diameter of the bend.
Such a bend is especially severe in the case of 6" pipe. This is shown in - 8 - 2~74~ 20 Figure 5 in which a 6" vehicle is shown negoti~ting a one diametor bend in distribution pipeline. The assembly 28 at the inside of the bend is shown in the condition it has when the vehicle i8 out3ide the pipeline, however.
In negotiating such a bend the sensor assembly 28 at the inside of the bend is required to collapse completely. This is possible owing to the nature of the leading and trailing members 46, 48. Under such conditions, the foil pack 24 at the inslde of the bend would bo roquirod to be deflocted right over until tho roarmost foil lay against the stop 70 (shown in Figuro6 1 and S) carried by the vehicle body 18, and against the upper edge 72, of the wings of the pressing 58. The foil pack 26 would be heavily deformed, adjAcent to the outer wall of the pipeline, and the rearmost foil would conform to the stop 74 (shown in Figure 1 and 5) carried by the vehicle body 18 .
Under certain conditions, the spring 64 might ongage the leading member 46 and tho trailing member 48.
For example, the size of tho pipe might demand a spring of such rhAr ~rtPri ctic3 that the 8pring occupiog nearly the whole of the space between the leading member 46 and the trailing member 48. Under running conditions in the pipeline 10 the spring 64 might cause the leading member 46 to bow outwards.
~owever, even under such conditions the spring still exerts a force on the sledge 40 which is substantially normal to the pipewall. Also, the motion of the vehicle is still transmitted to tho sledge 40 by the leading member 46 notwithstanding its bowed shape.
t As shown, the vehicle 16 is intended normally to travel in the direction of the ~rrow 30 shown in Figure 1, bein8 pulled by a haulage cabl~ tnot 3hown) l~ttached to 2 3wivel assembly 60 mountod on a pin 62 ~ecured to the leading end of the body 18. Another heulage cable ~not shown) for retrieving the vehicle 16 in reverse is attached to the eye 64 secured to the trailing end of the body 18.
The incpect~nn is carried out using the flux leakage method. A powerful magnetic field is generated by the eleL:L~, v c coil 20 and transferred into, and out of, the wall of the pipeline 10 by the foil packs 24, 26.
Electric current to energise the ele, L-, ~ c coil 20 is supplied from the surface Vi2 an umbilical supply cable (not shown) connected to the coil.
Defects, such as loss of metal due to corrosion in the wall of the pipe, cause magnetic flux to leak out of the wall of the pipe, and this is detected by the sensor within the housing 42. Each sensor transmits a C~nt~n~
signal as the vehlcl~ movell through the pipel~ne And thl~ ~lgm~l, with t signals from the other sensors, is sent down a aecond umbilical cable (not shown~ which extends from the vehicle to a personal computer with a hard disc recording facility ~t the surface of the ground. The position of the vehicle along the pipeline is known from ~ monitor measuring the length of haulage cable paid out by the winch.
In some cases (for example where an, ' 1;CA1 supply cable cannot be used) the ele.L, v LTc coil 20 i8 replaced by a pr ~ magnet or magnets.
The magnetic flux creAted by the ele.L, v t 20 circulates in a path, which includes the wall of the pipeline 10, the flux conductor or foil pack . ~ . . i - lo - 2 0 7 ~ 1 2 ~
26, the return path provided by the body 18 and the othor foil pack 24 forming the other flux conductor.
In other modifications (not shown) the path m~y include flux rcturn paths which are formed by members carried by the body, instead of the body itself providing the return path. For example, where permanent magnets are used instead of an ele.~L ~ L, the LLLIU4, may be as shown in British patent specification No. GB-B-1535252. In that ~re~;fi~ t;r~l the magnets sre flat plates having the magnetic poles at their broad faces and those faces are arranged parallel to the pipe inside surface. The magnets are arranged one at each end o~ flux return path members arranged around the body. The members are mounted on springs so as to move radially inward and outward to allow changes in diameter of the pipeline to be accommodated.
The flux conductors are mounted upon the magnets. The assemblies 28 would in that aLLa1.6 be mounted not on the body itself but on a ring which is "floating". That is, the ring surrounds the flux return path members and i8 connected to them by radial posts which pass through holes in the ring. The ring can thus move radially with respect to the flux return path members as the vehicle negotiates bends.
Claims (9)
1. A pipeline inspection vehicle for detecting defects in the wall of the pipeline comprising a body, two spaced apart flux conductors for engaging the inside of the pipeline, and means for generating flux either electromagnetically or by permanent magnetism, said flux being capable of circulating in a path including said wall, one of said conductors, said body or return path members secured to said body and the other of said conductors, the inspection vehicle further comprising an array of defect sensors arranged between said conductors, each sensor being mounted on an assembly which comprises a housing for the sensor, a sledge secured to the housing, and a spring interposed between said sensor housing and the body, in such a way that, when the vehicle is placed in the pipeline, the spring biases the housing and the sledge away from the body towardthe inside wall of the pipeline, said array being a circular array arranged around said body, each defect sensor being provided with its own assembly, in each assembly there being a leading member and a trailing member extending from the sledge to respective anchorages which are spaced apart in the direction of the length of the vehicle along a surface which is provided on, or connected to, said body and which is radially opposed to the housing, the anchorages being separated by a greater distance than the length of the sledge, said spring being positioned between said leading and trailing members against the sensor housing and againstsaid surface, said leading and trailing members being inextensible and each being readily collapsible under forces tending to make its ends become closer.
2. A vehicle according to Claim 1, each leading and trailing member comprising belting made of polymeric fibres.
3. A vehicle according to Claim 2, said polymeric fibres comprising polyurethane elastomeric material.
4. A vehicle according to Claim 1, said spring being made of non-metallic elastomeric material.
5. A vehicle according to Claim 4, said spring being made of polyurethane elastomeric material.
6. A vehicle according to Claim 4, said spring as viewed in side elevation being of 0 form.
7. A vehicle according to Claim 6, the 0 form having a flattened shape where it engages the vehicle.
8. A vehicle according to Claim 4, the sensor housing housing a shape which retains the spring against sideways displacement of the spring normal to the plane of the 0 form.
9. A vehicle according to Claim 1, the leading and trailing members both linking the assembly to said surface and the spring also engaging said surface, the surface being mounted on said body.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9115668.7 | 1991-07-19 | ||
| GB9115668A GB2257788A (en) | 1991-07-19 | 1991-07-19 | Pipeline inspection vehicle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2074120A1 CA2074120A1 (en) | 1993-01-20 |
| CA2074120C true CA2074120C (en) | 1996-09-17 |
Family
ID=10698671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002074120A Expired - Fee Related CA2074120C (en) | 1991-07-19 | 1992-07-17 | Pipeline inspection vehicle |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5351564A (en) |
| EP (1) | EP0523880B1 (en) |
| JP (1) | JPH0814574B2 (en) |
| CA (1) | CA2074120C (en) |
| DE (1) | DE69200649T2 (en) |
| ES (1) | ES2066559T3 (en) |
| GB (1) | GB2257788A (en) |
| HK (1) | HK1006996A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2286678B (en) * | 1994-02-18 | 1998-08-19 | Technical Software Consultants | A probe for an ACFM uniform field array testing system |
| GB9519368D0 (en) | 1995-09-22 | 1995-11-22 | Univ Durham | Conduit traversing vehicle |
| GB9617115D0 (en) | 1996-08-15 | 1996-09-25 | Astec Dev Ltd | Pipeline traction system |
| US6722442B2 (en) | 1996-08-15 | 2004-04-20 | Weatherford/Lamb, Inc. | Subsurface apparatus |
| US6198277B1 (en) | 1997-06-26 | 2001-03-06 | Gas Research Institute | Sensor module for use in system for inspecting in-service gas distribution mains |
| DE20000804U1 (en) * | 2000-01-19 | 2001-06-07 | Eder Gerhard | Pig, preferably inspection pig for electromagnetic testing of pipeline walls |
| GB0028619D0 (en) | 2000-11-24 | 2001-01-10 | Weatherford Lamb | Traction apparatus |
| US7051587B2 (en) | 2003-04-30 | 2006-05-30 | Weatherford/Lamb, Inc. | Traction apparatus |
| GB0505506D0 (en) * | 2005-03-17 | 2005-04-27 | Pll Ltd | A sensor system for an in-line inspection tool |
| US7256576B2 (en) * | 2005-07-29 | 2007-08-14 | General Electric Company | ID-OD discrimination sensor |
| US20070214994A1 (en) * | 2006-03-16 | 2007-09-20 | Pierson Construction Corporation | Pipeline traverse apparatus |
| CN101319983B (en) * | 2007-06-06 | 2011-09-07 | 中国石油天然气集团公司 | Probe spring of pipe corrosion detector |
| CN102768239B (en) * | 2012-08-07 | 2014-11-19 | 安庆市安科精机有限责任公司 | Magnetic flux leakage defection machine of oil sleeve |
| WO2017197505A1 (en) * | 2016-05-20 | 2017-11-23 | Desjardins Integrity Ltd. | System and method for detecting and characterizing defects in a pipe |
| EP3379222B1 (en) | 2017-03-22 | 2020-12-30 | Methode Electronics Malta Ltd. | Magnetoelastic based sensor assembly |
| CN107884471B (en) * | 2017-09-28 | 2021-04-20 | 北京华航无线电测量研究所 | Axial magnetic flux leakage signal defect detection method based on image processing |
| US11014417B2 (en) | 2018-02-27 | 2021-05-25 | Methode Electronics, Inc. | Towing systems and methods using magnetic field sensing |
| US11491832B2 (en) | 2018-02-27 | 2022-11-08 | Methode Electronics, Inc. | Towing systems and methods using magnetic field sensing |
| US11221262B2 (en) | 2018-02-27 | 2022-01-11 | Methode Electronics, Inc. | Towing systems and methods using magnetic field sensing |
| US11084342B2 (en) | 2018-02-27 | 2021-08-10 | Methode Electronics, Inc. | Towing systems and methods using magnetic field sensing |
| DE18907724T1 (en) | 2018-02-27 | 2021-03-25 | Methode Electronics, Inc. | Towing systems and methods using magnetic field measurement |
| US11135882B2 (en) | 2018-02-27 | 2021-10-05 | Methode Electronics, Inc. | Towing systems and methods using magnetic field sensing |
| US20210285914A1 (en) * | 2018-07-10 | 2021-09-16 | Pure Technologies Ltd. | Method and apparatus for electromagnetic testing of pipes |
| CN112888940A (en) * | 2018-08-08 | 2021-06-01 | 蓬勃科技有限公司 | Method and device for detecting defects of metal pipeline |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US957051A (en) * | 1909-05-20 | 1910-05-03 | American Water Main Cleaning And Contracting Co | Cleaner for mains and pipes. |
| US1620788A (en) * | 1925-12-10 | 1927-03-15 | John M Thompson | Device for passing cables through pipe lines |
| US1898074A (en) * | 1930-08-21 | 1933-02-21 | Carol Supplies Inc | Antifriction bearing |
| US2975637A (en) * | 1957-02-13 | 1961-03-21 | Statewide Plumbing & Heating C | Leak finder |
| US2972156A (en) * | 1959-01-05 | 1961-02-21 | Williamson Inc T | Pipeline cleaning device |
| US3162505A (en) * | 1961-08-21 | 1964-12-22 | Continental Oil Co | Device for locating pipeline leaks |
| US3449662A (en) * | 1963-10-16 | 1969-06-10 | American Mach & Foundry | Magnetic inspection method and apparatus using resilient magnetizing means and resilient sensors |
| CH490900A (en) * | 1967-06-28 | 1970-05-31 | Arx Paul Von | Device with the help of which the inner wall of a pipe can be cleaned and / or given a protective coating |
| US3483734A (en) * | 1967-11-03 | 1969-12-16 | American Mach & Foundry | Pipeline pigging apparatus |
| CA953364A (en) * | 1970-07-20 | 1974-08-20 | Amf Incorporated | Apparatus and method for pipeline inspection |
| US3754275A (en) * | 1971-09-17 | 1973-08-21 | Amf Inc | Method and apparatus for correlating a pipeline inspection record to known external locations |
| US3786684A (en) * | 1971-12-27 | 1974-01-22 | Automation Ind Inc | Pipeline inspection pig |
| US3837214A (en) * | 1973-01-30 | 1974-09-24 | Halliburton Co | Self-propelled pipeline plug |
| GB1535252A (en) * | 1976-04-09 | 1978-12-13 | British Gas Corp | Pipeline inspection vehicles |
| IT1147249B (en) * | 1981-12-02 | 1986-11-19 | Antonio Rognoni | MOBILE DEVICE FOR THE FILLING OF CONDUIT WITH FLUIDS, FOR THE EMPTYING AND DRYING OF THE SAME, AND FOR THE SEPARATION OF DIFFERENT FLUIDS DURING THEIR TRANSPORT IN CONDUCT |
| US4710711A (en) * | 1985-12-04 | 1987-12-01 | Western Atlas International, Inc. | Apparatus for nondestructive testing of subsurface piping using three coils with opposing fields |
-
1991
- 1991-07-19 GB GB9115668A patent/GB2257788A/en not_active Withdrawn
-
1992
- 1992-06-30 EP EP92306045A patent/EP0523880B1/en not_active Expired - Lifetime
- 1992-06-30 DE DE69200649T patent/DE69200649T2/en not_active Expired - Fee Related
- 1992-06-30 ES ES92306045T patent/ES2066559T3/en not_active Expired - Lifetime
- 1992-07-06 US US07/908,258 patent/US5351564A/en not_active Expired - Fee Related
- 1992-07-17 CA CA002074120A patent/CA2074120C/en not_active Expired - Fee Related
- 1992-07-20 JP JP4192271A patent/JPH0814574B2/en not_active Expired - Lifetime
-
1998
- 1998-06-23 HK HK98106175A patent/HK1006996A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| GB9115668D0 (en) | 1991-09-04 |
| EP0523880A1 (en) | 1993-01-20 |
| GB2257788A (en) | 1993-01-20 |
| EP0523880B1 (en) | 1994-11-09 |
| JPH0814574B2 (en) | 1996-02-14 |
| DE69200649D1 (en) | 1994-12-15 |
| ES2066559T3 (en) | 1995-03-01 |
| DE69200649T2 (en) | 1995-03-09 |
| CA2074120A1 (en) | 1993-01-20 |
| HK1006996A1 (en) | 1999-03-26 |
| JPH05188040A (en) | 1993-07-27 |
| US5351564A (en) | 1994-10-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |